WOFF Metadata - why reinvent the wheel?

Why does WOFF invent its own metadata format rather than reusing one of
the W3C's existing ones? RDF/XML or RDFa could easily express the kind of
data that WOFF seems to need.

The example in appendix A could be expressed in RDF/XML as:

<woff:WOFF
    xmlns="http://purl.org/dc/terms/"
    xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:woff="http://example.org/woff#"
    rdf:about="">
  <identifier>com.example.fontvendor.demofont.rev12345</identifier>
  <publisher>
    <foaf:Organization foaf:name="Font Vendor">
      <foaf:homepage rdf:resource="http://fontvendor.example.com" />
    </foaf:Organization>
  </publisher>
  <creator>
    <foaf:Person foaf:name="Font Designer"
      <foaf:homepage rdf:resource="http://fontdesigner.example.com" />
    </foaf:Person>
  </creator>
  <contributor>
    <foaf:Person foaf:name="Another Font Designer"
      <foaf:homepage rdf:resource="http://anotherdesigner.example.org" />
    </foaf:Person>
  </contributor>
  <contributor>
    <foaf:Person foaf:name="Yet Another" />
  </contributor>
  <description xml:lang="en">A member of the Demo font family.
            This font is a humanist sans serif style designed
            for optimal legibility in low-resolution environments.
            It can be obtained from fontvendor.example.com.
  </description>
  <license>
    <rdf:Description rdf:about="http://fontvendor.example.com/license">
      <identifier>fontvendor-web-corporate-v2</identifier>
      <description xml:lang="en">A license goes here.</description>
      <description xml:lang="fr">Un permis va ici.</description>
    </rdf:Description>
  </license>
  <rights xml:lang="en">Copyright ©2009 Font Vendor</rights>
  <rights xml:lang="ko">&#51200;&#51089;&#44428; ©2009 Font Vendor</rights>
  <woff:trademark xml:lang="en">Demo Font is a trademark of
             Font Vendor
  </woff:trademark>
  <woff:trademark xml:lang="fr">Demo Font est une marque
             déposée de Font Vendor
  </woff:trademark>
  <woff:trademark xml:lang="de">Demo Font ist ein eingetragenes
             Warenzeichen der Font Vendor
  </woff:trademark>
  <woff:trademark xml:lang="ja">Demo Font&#12399;Font
Vendor&#12398;&#21830;&#27161;&#12391;&#12354;&#12427;</woff:trademark>
  <woff:licensee foaf:name="Wonderful Websites, Inc." />
</woff:WOFF>

I've not included the example extension - RDF is inherently extensible -
indeed, the "woff:" vocab in the above is an off-the-cuff extension to the
well-established Dublin Core vocab.

It seems a mistake to reinvent the wheel when you could leverage a large
body of existing parsers, serialisers and other tools.

-Toby